The present invention relates to pipe couplings, and particularly to pipe couplings of the compression type, such as are described, for example in U.S. Pat. Nos. 4,025,093 and 4,083,587, assigned to the assignee of the present application.
Pipe couplings of this type generally comprise: a body member formed with a bore for receiving one end of a pipe to be coupled, an annular shoulder to enclose the pipe when received in the bore, and threads for threadedly receiving a securing nut; a sealing ring receivable within the bore and engageable with the annular shoulder for producing a sealing action with respect to the pipe when received in the bore; a compression sleeve also receivable within the bore and engageable with the sealing ring for compressing the sealing ring against the annular shoulder of the body member; a radially-deformable gripping ring having one end abuttable against the compression sleeve, and also having an inner surface producing a gripping action with respect to the pipe when the gripping ring is radially deformed; and a securing nut having threads mating with the threads on the body member and engageable with the gripping ring to move the gripping ring axially and to effect the sealing action via the compression sleeve and the sealing ring, and also to compress the gripping ring radially to effect the gripping action of the pipe received in the bore.
Pipe couplings of the foregoing type will hereinafter be referred to as xe2x80x9cpipe couplings of the type herein describedxe2x80x9d.
Pipe couplings of the type herein described, which are presently in wide-spread use, normally require pushing the pipe through the seal (typically an O-ring) in the bore of the body member in order to achieve compression of the O-ring on the pipe, and thus a leak free joint. However, for pipes of large diameters, the operation of pushing the pipe through the O-ring seal requires a large force, making the operation very difficult, and sometimes even necessitating an extra operation of chamfering the pipe end for this purpose.
A further disadvantage in pipe couplings of the type herein described now in use is that such couplings do not tolerate substantial variations in the pipe diameter so that precise pipe diameter tolerances must be maintained, or a large number of differences in diameter sizes; improved sealing even or damaged pipes, particularly since the seal produces double sealing points; and convenient disassembly of the coupling, since relaxation of the sealing ring releases the pipe end for removal and also xe2x80x9cspringsxe2x80x9d the compression sleeve, the split ring and the nut during disassembly.
Further features and advantages of the invention will be apparent from the description below.